JPH11286552A - Processing of elastomer dispersions - Google Patents

Abstract

(57) [Summary] (Modified) [PROBLEMS] To provide a method capable of adjusting the result of a grinding process even if it is not predictable, when it is desired to reduce the average particle size of an elastomer. The A linear alkenyl functionalized polyorganosiloxane and M ^H Q hydrosilylation addition product of a resin and a low molecular weight silicone comprising the composition when subjected to a new particle size reduction process to cause flow induced shear, unique Particle size distribution provides components for personal care formulations with improved coatability and quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to silicone compositions useful as thickeners for low molecular weight volatile silicones. The present invention also relates to a method of imparting fluidity to a gel-containing silicone by mixing a low molecular weight silicone with a gel and processing the mixture.

[0002]

BACKGROUND OF THE INVENTION Silicones have numerous uses in various fields. Silicones are widely applied commercially in a wide variety of products such as sealants, silicone rubbers, adhesives and cosmetics. Silicone oil has been found to be a particularly desirable component of cosmetic compositions because it is a material that has advantages such as increasing the apparent sheen (or gloss) and also provides a dry, smooth and uniform feel to the cosmetic composition. ing. While low molecular weight silicones impart desirable properties to the composition, they are somewhat cumbersome to use extensively in cosmetics in general because of their volatility and low viscosity, and silicones that overcome these disadvantages are too viscous. It is.

For example, where it is desired to utilize low viscosity silicone oils for cosmetic applications, thickeners have been used to increase solution viscosity and slow evaporation loss of volatile low molecular weight silicone oils. Although such treatments are effective, the applicability (sp
It has the disadvantage of reducing readability and leaving a heavy, sticky feel on the skin. The spreadability and dry, smooth feel are properties associated with low viscosity silicones which, when applied as cosmetics, give the composition a desirable feel or hand. Materials that have been applied to attempts to retain the desirable properties of low molecular weight silicone oils in cosmetic compositions while reducing evaporation loss due to high volatility include fatty acid esters of dextrin, fatty acid esters of sucrose, trimethylsilyl, among others. There are substituted polyvinyl alcohols, trimethylsilyl substituted polysaccharides, fatty acid ester-containing cellulose ethers, and organically modified clay minerals. These materials have the disadvantage of changing the light feel and coatability imparted by the low viscosity silicone oils, resulting in the loss of such properties from the composition. Suggests it is best to do so. Another disadvantage of these thickeners or volatilization inhibitors is that many of them are water-soluble and must be used as aqueous dispersions or solutions. The introduction of water along with the hydrophobic silicone oil requires the use of emulsifiers and compatibilizers, which complicates the formulation of cosmetics and generally reduces the stability of the formulation with respect to component phase separation.

Recently, another method for preserving the properties of low viscosity silicone oils in cosmetic compositions has been developed, in which low viscosity silicone oils are treated with organohydrogenpolysiloxanes and alkenyl-functionalized organopolysiloxanes. (US Pat. No. 4,987,169). The organohydrogenpolysiloxane utilized in such formulations is H
SiO _1.5 (T ^H ) group, RSiO _1.5 (T) group, RHS
iO (D ^H ) group, R ₂ SiO (D) group, R ₂ HSiO _0.5
(M ^H ) group and R ₃ SiO _1.5 (M) group.
Crosslinking hydride compound utilized is therefore the general formula: is a compound of ^{_{M a M H b D c D}} H d T e T H f. It is said that in this cross-linking compound, the T group may be a hydride or a compound substituted by R. However, the priority in this technique is higher for a linear hydride material because addition polymerization proceeds more smoothly. The R groups in these formulas are typical organic substituents known in the art. Next, a low molecular weight silicone oil is added to the crosslinked addition polymerization product, and the mixture is treated by applying a shearing force. This material can be used by itself as a cosmetic ingredient or as a thickener, has grease properties and can be used for a wide range of industrial lubrication applications as well as cosmetic applications. The material produced in this way can be regarded as a low cross-linking elastomer in which volatile low molecular weight silicone oil is dissolved. Since the crosslinking hydride as a precursor is preferably linear and only moderately branched, even if T groups are incorporated, the addition polymerization product is:
There is no dense crosslinked network in the resulting polymer. A linear, low cross-linking network suffers from the low thickening efficiency of low molecular weight silicones. In addition to increasing the cost of the product, high concentrations of cross-linked silicone result in large amounts of residue being left as the volatile low molecular weight silicone evaporates during use. In some cosmetic applications, such as deodorants and antiperspirants, increasing the amount of residue is very disadvantageous because it contributes to garment staining.

[0005] In addition, the linear, low-crosslinking silicone is
It does not form a film as easily as a more densely crosslinked silicone. Lack of film formation is disadvantageous in cosmetic applications. This is because the membrane gives a soft and smooth feel compared to the heavy and less desirable feel of linear silicone. For solids, the size reduction process generally results in a change in both the average particle size and the particle size distribution. For most solid materials, milling techniques typically reduce the average particle size, resulting in a Gaussian particle size distribution. Accordingly, technical literature on milling techniques focuses on controlling the width of the Gaussian distribution (ie, how wide or narrow the particle size distribution). The width of the particle size distribution is generally a property measured by the width of the distribution peak at half the height of the peak of the most frequent particle size. This is commonly called half-width measurement.

[0006] Emulsions can also be subjected to a grinding process, with results similar to those obtained with solid processes. The initial particle size and particle size distribution of the immiscible liquid dispersed in the second liquid phase is converted to a smaller average particle size.
Typically, the particle size distribution of the discontinuous phase in the emulsion, whether measured before or after grinding, is best described by a Gaussian distribution.

[0007]

In contrast to the predictability of the milling process known for solids and dispersions, soft solids such as polymers do not respond in a classical manner. Emulsions do not make a difference when sheared in different ways to reduce the average particle size, whereas soft polymers, on the other hand, often have random sizes and shapes that are random. Thus, if it is desired to reduce the average particle size of the elastomer, it would be an advance in technology if the results of the milling process could be adjusted even if not predictable.

[0008]

Means for Solving the Problems] We, to provide a component having a unique particle size distribution of the dressed in cosmetic compositions, elastomers crosslinked closely produced in the addition polymerization of an alkenyl organopolysiloxane and M ^H Q resin Is combined with a volatile low molecular weight silicone oil to provide flow induced shear.
(ced shear).

The present invention provides a method comprising: a) applying a pressure to a dispersion in which an elastomer having an initial average particle size and a particle size distribution is dispersed in a solvent; b) subjecting the dispersion to a pressure drop through an orifice; Passing through the orifice to reduce the initial average particle size of the dispersion; c) repeating steps a) and b), thereby adjusting the particle size distribution so that the particle size distribution is in the range of about 21 to about 26 microns. E) including a maximum in the range of about 33 to about 38 microns, and f) including a maximum in the range of about 50 to about 60 microns.

The present invention also provides: a) subjecting a dispersion in which an elastomer having an initial average particle size and particle size distribution is dispersed in a solvent to a pressure drop using an orifice, whereby the dispersion is dispersed through the orifice. B) repeating step a) and adjusting the particle size distribution so that the particle size distribution is c) maximal in the range of about 21 to about 26 microns; d) about 33 to about 38 microns. And e) providing a maximum in the range of about 50 to about 60 microns.

[0011]

The composition of a specific embodiment of the DETAILED DESCRIPTION OF THE INVENTION The present invention provides (1) the _{^{formula: M vi a D x D vi}} y M 2-a [ where several code x is greater than 500 , Preferably 600
More preferably more than 700, most preferably more than 800, and a + y is from 1 to about 2
0, preferably 1 to about 10, more preferably about 1.5
The symbol y may be from 0 to about 20, preferably from 0 to about 10, more preferably from 0 to about 5, most preferably from 0 to about 10, most preferably from 0 to about 10, most preferably from about 1.5 to about 6. Preferably, it is a number from 0 to about 4, the symbol a is a number from 0 to 2, and M ^vi is R ¹ R ² R ³ SiO _1/2 (R ¹ is a monovalent unsaturated unsaturated compound having 2 to 10 carbon atoms). A hydrocarbon group, preferably a styryl, allyl and vinyl group, more preferably an allyl and vinyl group, and most preferably a vinyl group, and R ² and R ³ each independently have 1 to 1 carbon atoms.
40 monovalent hydrocarbon groups, preferably 1 to 20 carbon atoms
A monovalent hydrocarbon group, more preferably methyl, ethyl,
Propyl, isopropyl, n-butyl, isobutyl, s
ec-butyl, tert-butyl, pentyl, hexyl, heptyl, phenyl, benzyl and mesityl groups, most preferably selected from the group consisting of methyl and phenyl), wherein D is R ⁴ R ⁵ SiO _2/2 (R ⁴ and R ⁵ are each independently a monovalent hydrocarbon group having 1 to 40 carbon atoms, preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, more preferably methyl, ethyl, It is selected from the group consisting of propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, phenyl, benzyl and mesityl groups, most preferably the group consisting of methyl and phenyl. D ^vi is D ^vi = R ⁶ R ⁷ SiO _2/2 (R ⁶ is a monovalent unsaturated hydrocarbon having 2 to 10 carbon atoms) R ⁷ is preferably a styryl, allyl and vinyl group, more preferably an allyl and vinyl group, most preferably a vinyl group, and R ⁷ is independently a monovalent hydrocarbon group having 1 to 40 carbon atoms, preferably A monovalent hydrocarbon group having 1 to 20 carbon atoms, more preferably methyl, ethyl, propyl,
Isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, phenyl, benzyl and mesityl groups, most preferably selected from the group consisting of methyl and phenyl) M is defined as: M = R ⁸ R ⁹ R ¹⁰ SiO _1/2 (R ⁸ , R ⁹ and R ¹⁰ are each independently a monovalent hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 40 carbon atoms. 20 monovalent hydrocarbon groups, more preferably methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-
The group consisting of butyl, tert-butyl, pentyl, hexyl, heptyl, phenyl, benzyl and mesityl groups;
Most preferably is selected from the group consisting of methyl and phenyl) and a linear alkenyl-terminated polyorganosiloxane of the formula (M): (M ^H _w Q _z ) _{j wherein} Q _{Has the} formula SiO _4/2 , and ^MH is H _b R ¹¹ _3-b SiO _1/2 (the symbol b is a number from 1 to 3, and R
¹¹ is a monovalent hydrocarbon group having 1 to 40 carbon atoms, preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, more preferably methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl. , Tert-butyl,
Pentyl, hexyl, heptyl, phenyl, benzyl and mesityl groups, most preferably selected from the group consisting of methyl and phenyl), wherein the symbols w and z are from 0.5 to 4.0, Preferably 0.6-3.5, more preferably 0.75-3.0,
Most preferably it has a ratio of 1.0 to 3.0, and the symbol j is about 2.0 to about 100, preferably about 2.0 to about 30, more preferably about 2.0 to about 10, most preferably Is about 3.
A number from 0 to about 5.0], and (3) a silicone, comprising a mixture of the addition product of (1) and (2) and (3). Subjected to shear forces that affect the average particle size distribution, the distribution has certain unique properties.

The hydrosilylation reaction comprises ruthenium,
It is carried out in the presence of a hydrosilylation catalyst selected from the group consisting of osmium, rhodium, iridium, palladium and platinum hydrosilylation catalysts. Specific examples of such catalysts are described in U.S. Pat. Nos. 2,823,218 and 315,960.
No. 1, No. 3,159,662 and No. 3,775,452.

The silicone of component (3) has a viscosity of about 10 at 25 ° C.
It is defined as an organosilicon compound having a viscosity of less than 00 centistokes, but is preferably
Viscosity less than centistokes, more preferably 25 ° C
Less than about 250 centistokes, most preferably less than about 100 centistokes at 25 ° C. Thus, D ₃ , D ₄ , D ₅ and D ₆ (ie, D f where the code f is in the range of 3-6, where D _f
Is as defined above, wherein R ⁴ and R ⁵
Low molecular weight cyclic silicones such as is preferably methyl), and the following formula: M'D _'i M' [wherein, D 'are independently selected from the same substituents as defined for D above Wherein M ′ is the following formula: R ¹² R ¹³ R ¹⁴ SiO _1/2 (R ¹² , R ¹³ and R ¹⁴ each independently have 1 to 40 carbon atoms.
Monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, more preferably methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec
-Butyl, tert-butyl, pentyl, hexyl, heptyl, phenyl, benzyl and mesityl groups, most preferably selected from the group consisting of methyl and phenyl); From about 300, preferably from 0 to about 100, more preferably from 0 to about 50, and most preferably from 0 to about 20] are such volatile silicones. Preferably, component (3) is a volatile low molecular weight silicone.

The materials used for preparing the gel of the present invention are as follows:
It has been defined by formulas using structural elements M, D, T and Q belonging to definitions generally accepted in the field of silicone chemistry. As individual molecules or pure compounds, the sign of each of the above formulas can only take on integer values (including 0 as appropriate). As a complex compound of a plurality of compounds (each of which satisfies the above molecular definition), the code representing the mixture may take on a value other than an integer (including 0 as appropriate). However, even if a code takes a value other than such an integer, the value is between the upper and lower limits of the range when the code is defined as an integer value. For example, when representing a pure compound of the component (1), the symbol a can take a value of 0, 1 or 2. As a mixture of a plurality of compounds, component (1) is the average value for the symbol a,
And the number of species having a equal to 2. The same is true for components (2) and (3).

Thus, when component (1) is a specific alkenyl-functionalized vinyl-functionalized silicone and is a mixture of various vinyl-containing compounds, the average sign of component (1), by definition, is the vinyl equivalent Approximately 15
00 to about 150,000, preferably about 4500 to about 11
0000, more preferably about 10,000 to about 7000
0, and most preferably ranges from about 15000 to about 45000. These equivalents are specific equivalents for the vinyl substituent, and the equivalent ranges generated when substituted with another olefinic substituent are almost the same, though different. Similarly, the average sign of component (2) as a mixture is, as defined, about 80 equivalents in hydride equivalents.
To about 190, preferably about 82 to about 170, more preferably about 85 to about 150, and most preferably about 87 to about 1
Over a range of 30.

Further, the alkenyl functional groups present in component (1) desirably range from an average of about 1 to about 20 alkenyl groups per molecule, preferably from about 1 to about 10 alkenyl groups per molecule. Groups, more preferably about 1.5 to about 10 alkenyl groups per molecule, most preferably about 1.5 to about 6 alkenyl groups per molecule. In addition, the hydride functionality present on component (2) averages from about 8 to about 400 S molecules per molecule.
Desirably in the range of iH groups, preferably from about 8 to about 100 SiH groups per molecule, more preferably 1 to about 100
It is in the range of about 8 to about 50 SiH groups per molecule, most preferably about 8 to about 20 SiH groups per molecule.

Components (1) and (2) (both as pure compounds or mixtures) catalyze in the presence of component (3) to form a gel with a certain polymer content, but the approximate polymer content The amount is about 5 to about 75% by weight of the crosslinked polymer, preferably about 10 to about 60% by weight of the crosslinked polymer,
More preferably, about 15 to about 40% by weight of the crosslinked polymer,
Most preferably, from about 20% to about 35% by weight of the crosslinked polymer, with the balance being a volatile low molecular weight silicone oil.
Once this initial product gel is prepared, it is added to an additional amount of a volatile low molecular weight silicone (ie, additional component (3), which may be different from component (2) used to prepare the initial product gel). And subject to mixing or shearing to form a uniform liquid gel. The uniform liquid gel comprises about 1 to about 25% by weight of the crosslinked polymer, preferably about 2 to about 20% by weight of the crosslinked polymer, more preferably about 3 to about 15% by weight of the crosslinked polymer, and most preferably about 3 to about 15% by weight. Component (3) or a mixture of various compounds meeting the definition of component (3), with about 10% by weight, the balance being volatile low molecular weight silicone oils.

The initially formed gel is sufficiently viscous that liquid flow is not normally observed. As a crosslinked polymer substance, a gel having a crosslinked polymer network structure of 25% by weight which is initially formed is 5 or more, preferably 7 or more, more preferably 10 or more.
As described above, it most preferably has a durometer hardness (ASTM D-2240-91) of 15 or more. The ASTM test value for the durometer hardness test is an indication that the material has sufficient flow resistance to be able to be characterized as just a solid.

In recent years, the personal care industry has found that the use of various silicone polymers, from very low to very high molecular weight, provides improved product flow and a smooth, non-greasy feel in a wide range of applications. Being done. For example, silicone polymers have been used in formulating antiperspirants / deodorants, skin lotions, creams, hair care products, cosmetics, and the like. While these silicone polymers provide the desired performance characteristics to personal care products, they have traditionally required delivery systems that include non-silicone-based thickeners. Such non-silicone thickeners are generally undesirable because they have a detrimental effect on the intended silicone feel.

Recent techniques that teach the use of crosslinked silicone polymers in thickeners include the use of crosslinked silicone polymer particles that produce excellent performance characteristics including a smooth, silky feel and high viscosity for optimal thickening effect. Lack of awareness of the need to create unique and desirable distributions. This technique does not precisely define a method for producing the most desirable distribution of these particles. Further, some of the processing methods suggested in this technique are limited to only a small range of cross-linked silicone polymers that can be useful in the present invention. Thus, as the type of cross-linked silicone polymer changes to provide the desired more efficient use of the polymeric material, low levels of compression (such as colloid mills), mechanical shearing (rotor / stator mills) or Shearing with break (hammer mill) does not give the desired crosslinked silicone polymer particles with the required particle size and distribution. In addition, there is no provision for economically processing crosslinked silicone polymers.

It has now surprisingly been found that the process comprises the use of silicone particles having a unique particle size distribution to provide a thickener for the silicone dispersion medium. In addition to providing an economical method of processing crosslinked silicone polymers, the use of high flow induced shear and particle elongation also provides a unique and highly desirable particle size that provides the desired smooth and silky feel while maintaining high viscosity and thickening A distribution was found to occur. In addition, this processing method is applicable to any range of desired crosslinked silicone polymers.

While some physical properties of the thickener are determined by the chemical structure of the crosslinked silicone polymer, the particle size and its distribution are key to the highly desirable thickening (viscosity) and feel of the product. An effective thickening behavior is the result of the presence of a large particle size that increases the fluid viscosity. The size of the large particles is limited by the need to avoid particles that are large enough to form a gel sphere that is visible in use. An excellent feel is the result of the generation of small particles that improve smoothness when spread on the skin. If the crosslinked silicone polymer disintegrates into too small particles or a homogeneous fluid, the feel becomes heavy and sticky, which is undesirable. Thus, the preparation of an effective thickener with an excellent feel requires the ability to generate a wide distribution of particles.

Surprisingly, the use of flow-induced shear and particle elongation, particularly at high stress levels, in the processing of crosslinked silicone polymers results in a unique particle size distribution. While it is common to predict that fracture of particles using stress will result in a unimodal or even bimodal distribution, especially high flow-induced shear and particle elongation may give a multimodal distribution of particle sizes. found.

In earlier experiments, the particles prepared according to the invention did not swell well with thin materials having an elastomer content of 5% and a cyclic siloxane of 95%. However, when the elastomer is further diluted to less than about 3% elastomer content, the particles swell completely. Thus, the particle size as referred to in the present invention is for sufficiently diluted particles, but the actual volume, although used in most applications, is small depending on the amount of solvent available. For a given particle composition, it is possible to measure how much additional solvent can be absorbed, so that knowing the size of the sufficiently diluted particles, it is possible to calculate the particle size back at any concentration. It is also within the scope of the present invention to prepare relatively small particles at a relatively high elastomer concentration and then swell it with an additional solvent to a large particle size.

In the products of the present invention, the particle size distribution contains a plurality of frequently overlapping individual particle populations. Together they give a broad distribution of large and small particles, resulting in high efficiency and viscosity as well as good feel and lubricity. Individual particle populations generally fit a lognormal particle size distribution,
It is measured over the entire range from about 10 microns on average to about 600 microns on average. When the particles are not fully swollen for a particular application, the population of particle sizes, or particle size distributions, will range accordingly to smaller particle sizes and shift to smaller particle size ranges. The particle size distribution includes a continuous plurality of identifiable particle populations ranging from less than about 1 micron at swelling to about 600 microns after swelling. The average particle size range when measured in a completely swollen state is from about 1 to about 500
It preferably covers from about 1 micron to about 400 microns, more preferably from about 1 to about 400 microns after solvent swelling, and most preferably from about 1 to about 300 microns.

The composition of the present invention is characterized in that the composition is a dispersion in which an organic polymer elastomer (preferably a silicone elastomer) is dispersed in a suitable solvent.
There are three maxima in the particle size distribution: 1) maxima in the range of about 21 to about 26 microns, 2) maxima in the range of about 33 to about 38 microns, and 3) maxima in the range of about 50 to about 60 microns. Characterized by having a particle size distribution characterized by As maxima, these three maxima appear as identifiable peaks in the diagram showing the relationship between population and particle size. It should be emphasized that the composition of the present invention may have other maxima in addition to these three maxima in the diagram showing the relationship between the population and the particle size, but these three maxima are always present. Depending on the other characteristics of the particle size distribution, the main properties of the composition are from the so-called stiff creamy feel when the distribution is biased towards the larger particle size, to the distribution when the distribution is centered around these three maxima. It changes to a light creamy feel and a heavy, sticky feel when the distribution is biased toward the smaller particle size side. These values are specific to the particle size distribution analyzer method, specifically using a Malvern Mastersizer with a 300 mm lens.

[0027] The process of making the crosslinked silicone polymer particles suitable for use in the present invention involves preparing a crosslinked silicone polymer, often in a low molecular weight silicone fluid. This material may then be further swollen with an additional solvent, which may be the same or different from the solvent used to prepare the crosslinked silicone polymer. The crosslinked silicone polymer is then broken down into small particles, often in an additional silicone fluid. It is an observation of the present invention that the superior method of breaking down polymers into small particles is by high flow induced shear. In this method, a slurry containing a cross-linked silicone polymer and a desired solvent is first diluted, and then flow-induced shear and particle elongation through an orifice under pressure. In this way, flow induced shear and particle elongation occur in the entry region to the orifice as well as as the material passes through the orifice. It is this flow-induced shear and particle elongation that ultimately tears the crosslinked silicone polymer into small particles, although some material may be cut off at the edge of the orifice.

The magnitude and profile of the flow induced shear in this process depends on the pressure, orifice geometry,
It is controlled by several parameters, including fluid viscosity, which to some extent reflects fluid temperature, fluidity, and shear properties. Pressure may be defined as the pressure drop through an orifice. As the pressure drop increases, so does the flow-induced shear, and the crosslinked silicone polymer is ground more quickly to give the desired particle size and a wider, more desirable distribution.
In general, for a given orifice geometry and fluid viscosity, high flow induced shear is associated with high pressure drop.

At a given pressure drop, the orifice geometry also determines the nature of the high flow induced shear. The geometry of the orifice is a very versatile property, and various shapes and sizes are possible. For example, the shape of the opening of the orifice may be round, oval, rectangular, or annular.
Such orifices may be completely open or have pins or other obstructions in the openings. The opening may be provided at one location, or a plurality of openings having the same or different geometric structures may exist. In general, the larger the orifice at the same pressure drop and fluid viscosity, the wider and more desirable the particle size distribution. Similarly, the length of the flow path through which the fluid passes may be long or short, and may be linear or curved. In general, the shorter the length of the orifice, the greater the flow-induced shear, resulting in particles of smaller size and broader distribution. The size of the orifice also affects the flow-induced shear at the entrance to the orifice. That is, the larger the ratio, the wider the particle size distribution so that the material flows from the larger diameter tube to the smaller orifice.

[0030] Fluid viscosity also determines flow induced shear. As the viscosity of the fluid increases, the flow induced shear increases, with the desired result. Viscosity is affected by temperature,
A low and constant temperature that gives a relatively high viscosity is desirable. Similarly, materials that exhibit shear thinning (some silicones are known to exhibit such behavior) have low flow-induced shear at the orifice, thereby increasing particle size and narrowing the distribution. Although the viscosity of the initial slurry of the elastomer subjected to the present process may be difficult to measure, the viscosity can be measured after the processing, and the viscosity of the elastomer dispersion increases after several initial processes. Since the material to be processed is a dispersion or suspension of elastomer particles dispersed or suspended in a solvent, the viscosity can be affected by the so-called solids level. As the solids level increases, ie, as the amount of solvent present gradually decreases, the flow resistance increases, which can sometimes be measured as an increase in viscosity.

These parameters as a whole are key factors in determining flow induced shear. Depending on the particular environment, any one or more of these three parameters can be a major (ie, most important) factor in determining the actual flow-induced shear. The high dynamic shear is sufficient to grind the crosslinked particles to the desired size and distribution. In some cases, this may be accomplished with only one pass through the orifice, or it may need to be passed several or more times to achieve the desired particle size. In general, reducing the number of passes and broadening the particle size distribution is desirable from an economic and performance standpoint and can be obtained by high flow induced shear.

Flow induced particle elongation occurs when the crosslinked silicone polymer is swept under pressure toward the orifice and converges from a large diameter environment to a small diameter opening. The particles elongate as they pass through this area, producing small particles. Important factors include pressure, fluid viscosity, and cross-sectional area ratio between the supply chamber and the orifice. When the pressure increases,
Increased particle elongation results in more efficient particle size breakage. Similarly, as fluid viscosity increases, particle elongation increases. As the cross-sectional area ratio between the supply chamber and the orifice increases, the degree of particle elongation increases. In general, increasing particle elongation increases the efficiency of grinding the particles and reduces the number of passes required.

The desired pressure range for sufficient flow induced shear and particle elongation is above 500 psi. The pressure range is preferably above 1000 psi, more preferably 1
More than 500 psi, most preferably more than 2000 psi. The viscosity should be above 500 ctsk. The viscosity is preferably above 750 ctsk, more preferably above 1000 ctsk and most preferably above 500 ctsk.
Should be greater than 0 ctsk. The dimensions of the orifice
Limited by the ability of the delivery system to maintain sufficient pressure. As a practical matter, the size of the orifice is desirably less than 0.5 square inches, preferably less than 0.1 square inches, more preferably less than 0.05 square inches, and most preferably less than 0.01 square inches. is there.

The interaction of all of these working variables together provides a process that reduces the average particle size of the elastomer dispersion and produces a unique particle size distribution. Generally, unless the elastomer dispersion is processed at a very high pressure drop, conversion to the desired composition is not achieved in a single pass. Thus, there is a correlation between the applied pressure drop and the number of times the elastomer dispersion must be passed through the processing equipment to convert the material to the desired composition. This is reflected in the following dimensionless relation, which determines the number of passes N _p necessary to produce a material that meets the conditions for a given pressure drop P _d .

N _p = 82799 P _d ^(-1.1696) This equation is somewhat arbitrary and depends on the definition of what constitutes a material that ^meets the conditions. 1) maximum in the range of about 21 to about 26 microns in particle size distribution; 2)
Maxima in the range of about 33 to about 38 microns and 3) about 50
Materials having a particle size distribution characterized by three peaks (i.e., three maxima) at a maximum in the range of ~ 60 microns are considered qualifying materials.

Further, a dimensionless relational expression relating the obtained average particle size S _p (avg) (measured with a Malvern Mastersizer (trademark)) to the pressure drop P _d , the orifice cross-sectional area O _a and the number of passages N _p. Can be made. Here _{S p (avg) = K +} C 1 P d + C 2 O a + C 3 N p, K is the intercept, coefficients each C _i is associated with each variable, i.e., C ₁ is the pressure drop coefficient, C ₂ the orifice cross-sectional area coefficient, C ₃ is the number of passes coefficient. The various working ranges are shown in the table below.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

Since the number of passes N _p is correlated with the pressure drop P _d , the equation for the number of passes can be substituted into the average particle size equation. This mathematical substitution emphasizes the strong pressure drop dependence of the process. Briefly, the method of the present invention (to obtain the composition of the present invention) involves subjecting the elastomer dispersion to pressure, passing through an orifice at a particular pressure drop, reducing the average particle size, and reducing the particle size distribution. It is a process that produces a certain maximum. The process of achieving such conversion by pressure drop and orifice is all the method of the present invention. It should be noted that the pressure drop referred to herein has the dimension of pounds per square inch (psi), the orifice cross section has the dimension of square inches (in ² ), and the particle size or average particle size has the dimension of microns. . As the orifice size decreases, the pressure must be increased to maintain throughput. Therefore, the smaller orifice size in the above range is described in the column with the heading "Maximum". This is because small orifice sizes and large pressures have the same overall effect.

Finally, it should be emphasized that the intercepts and coefficients of the process variable equations may vary depending on the particular machine used. The data presented herein are representative of correlation results for some particular machines and are exemplary rather than defined or limited. So, while defining the process variables fairly accurately, the intercept K and the coefficients C ₁ ,
C ₂ and C ₃ are more likely to deviate from the values described herein than are actual process variables. Regardless of the actual machine and process conditions used and the actual values of the intercepts and coefficients of the process variable relations, all processes for converting the granularity to those defined herein are within the scope of the claims.

The development of the desired particle size is determined in part by the degree of swelling of the particles prior to applying flow induced shear and particle elongation. As the particles swell with the solvent, internal stresses develop, reducing the level of shear and particle elongation required to tear the particles. Therefore, if the degree of swelling of the crosslinked silicone polymer in the slurry to be processed is high or the concentration is low,
The internal stress increases and the efficiency of the process increases. It is desirable to dilute the crosslinked polymer concentration to less than 60% solids by weight. Preferably, the crosslinked silicone polymer swells or dilutes to less than 50% solids by weight, more preferably swells the crosslinked polymer to less than 40% solids, and dilutes the crosslinked polymer to less than 30% solids content. Is most preferred.

The flow resistance of the initially formed gel is overcome by high speed mixing or shearing and the resulting composition or mixture becomes a homogeneous liquid at 25 ° C. from about 500 to about 1500.
00 centistokes, but more preferably the resulting composition or mixture has a viscosity of about 1000 to about 100,000 centistokes at 25 ° C, and most preferably the resulting composition or mixture has a viscosity of 25 centistokes. About 10,000 to about 60,000 centistokes at ° C. The term shear means applying a force to the composition and the mixture is a two-roll mill, a colloid mill, a Gaulin homogenizer, a Sonorator, a Ross (TM) mixer, a micro mixer. Fluidizer (Microfluid
izer).

When these compositions are subjected to shearing forces, the presence of the compositions of the present invention having a unique particle size distribution results in components having improved coatability and quality or feel suitable for personal care or cosmetics. Occurs. Personal care applications where this property is most desired include, but are not limited to, deodorants, antiperspirants, skin creams, facial creams, hair care products such as shampoos, mousses, styling gels, protective creams, color cosmetics such as lipsticks, There are those in foundations, blushers, make-ups, mascaras, and even other cosmetics in which the addition of silicone components has previously been made. The elastomer dispersion processed by the method of the present invention comprises an elastomer gel and a low molecular weight silicone. The method of the invention used to obtain the composition of the invention is applicable to elastomer dispersions or gel dispersions or gels.

The disclosures of all United States patents cited herein are hereby incorporated by reference.

[0047]

EXAMPLES Example 1: In volatile low molecular weight silicone oil
Preparation of Crosslinked Silicone Polymer A crosslinked silicone polymer was prepared by mixing predetermined silyl hydride species, predetermined vinyl species and volatile low molecular weight silicone oil in a reaction vessel. To this mixture, a standard hydrosilylation catalyst was added. Hydrosilylation in the presence of a platinum catalyst is disclosed in US Pat.
No. 601, No. 3159662, No. 3220972
Nos. 3,715,334, 3,775,452 and 3,814,730, the disclosures of which are incorporated herein by reference. The mixture containing the hydrosilylation catalyst was heated and reacted under predetermined conditions. For example, (M ^H ₂ Q) ₄ (w = 2, z = 1,
j = 4) 1.11 g, 33750 g / equivalent of vinyl-equivalent 250 g of vinyl-terminated siloxane and 650 g of octamethylcyclotetrasiloxane were put into a dough mixer and stirred. 0 in octamethylcyclotetrasiloxane.
100 g of 11% platinum catalyst was added. Stir the reaction system 8
Heated to 0 ° C. for 2 hours. The reaction was cooled and the product was isolated. Compositions AT were prepared according to this general procedure. The vinyl siloxane in these samples was variously changed as follows.

1) Divinylsiloxane (A) has M^viD_x
M^viWhere M^viIs R¹R^TwoR^ThreeSiO_1/2Is
Is R¹Is (CH_Two= CH) and R^TwoAnd R^ThreeIs German
Standing CH_ThreeAnd D is R^FourR^FiveSiO_2/2Is
Is R^FourAnd R^FiveAre each independently CH_ThreeAnd x is about 45
From 0 to about 1250; 2) monovinylsiloxane (B) is M^viD_yM,
Where M^viIs R¹R^TwoR^ThreeSiO_1/2Where R¹Is (C
H_Two= CH) and R^TwoAnd R^ThreeAre each independently CH_ThreeIn
And D is R^FourR^FiveSiO_2/2Where R^FourAnd R^FiveIs
CH independently_ThreeWhere y is approximately equal to 200 and M
Is R⁸R⁹R^TenSiO_1/2Where R⁸, R ⁹And R^TenIs
CH independently_Three3) Pentavinylsiloxane (C) is MD_iD^vi _kM
Where M is R⁸R⁹R^TenSiO_1/2Where R⁸, R
⁹And R^TenAre each independently CH_ThreeAnd D is R^FourR^FiveSiO
_2/2Where R^FourAnd R^FiveAre each independently CH_ThreeAnd i
Is approximately equal to 200 and D^viIs R⁶R⁷SiO_2/2Is
Is R⁶Is (CH_Two= CH) and R⁷Is independently CH_Threeso
And k is approximately equal to 5.

[0049]

[Table 5]

Samples A to G were obtained by examining the change in the hydride to vinyl ratio in the hydrosilylation reaction. Samples E, H and I were obtained by examining the change in the molecular weight of the vinyl component in the hydrosilylation reaction. Standards E and J
Is a study on the change of volatile low molecular weight silicone oil. In contrast to the preparations shown in Table 1, which use only one vinylsiloxane compound, divinylsiloxane A, the following preparations use a mixture of two vinylsiloxane compounds, divinylsiloxane A and monovinylsiloxane B. did.

[0051]

[Table 6]

Samples KO were obtained by changing the ratio of divinylsiloxane A to monovinylsiloxane B at a fixed hydride to vinyl ratio. Standards PR are
The ratio of divinylsiloxane A to monovinylsiloxane B was changed at a fixed hydride-to-vinyl ratio different from the standards KO. Divinylsiloxane A
In contrast to the samples shown in Table 1 where only one type of vinylsiloxane compound was used, the following samples utilized a mixture of two types of vinylsiloxane compounds, divinylsiloxane A and pentavinylsiloxane C.

[0053]

[Table 7]

The specimens shown in Table 3 are the same as the specimens shown in Table 2.
The mixture of vinylsiloxanes used in the preparation of the crosslinked product is different. Example 2: Crosslinking gel with volatile low molecular weight silicone oil
The crosslinked gel produced in Dilution Example 1 was further diluted with a volatile low molecular weight silicone oil to form a slurry. The volatile low molecular weight silicone oil used for dilution was the same or different from that used for preparing the crosslinked gel. The slurry was subjected to shear in a homogenizer to yield a clear product of the viscosity desired for the particular cosmetic application. The viscosity of the gel volatile slurry subjected to shearing force is about 100 at 25 ° C.
It ranged from centistokes to over 100,000 centistokes. For example, a 400 g sample E
Was blended with 1600 g of D ₄ (octamethylcyclotetrasiloxane). Preparation E 25% by weight of crosslinked polymer, i.e. contains 100 g, E in D ₄ above
Has a polymer concentration of 5% by weight. This mixture of D ₄ 5 wt% cross-linked polymer was passed through a Gaulin homogenizer at pressures of 7000 psi. The resulting material was clear and had a viscosity of 120,000 centistokes at 25 ° C. The preparation of other materials according to this general procedure is shown in Table 4.
Shown in

[0055]

[Table 8]

These data indicate the following. 1) As the hydride to alkenyl (vinyl) ratio changes from 0.7 to 1.6 hydride to 1.0 alkenyl, the resulting gel viscosity increases. 2) As the molecular weight of the alkenyl component increases, The distance between the cross-linking sites is widened, and the swelling ability of the initially formed polymer gel upon addition of the volatile silicone is increased, and the viscosity is increased.
Increases the crosslink density and increases the viscosity of the resulting product.

Example 3 Low Crosslink Density Gel and High Crosslink Density Gel
Comparative processed gels of the invention, the the use of equivalent rather low vinylsiloxane and M ^H Q resin of a vinyl group,
Has a high crosslinking density. For comparison, low crosslink density gels were prepared. The procedure outlined for the preparation of the gel of Example 1 was utilized with a (average) linear hydride siloxane containing only 2 equivalents of hydride per molecule and a vinyl siloxane containing only 2 equivalents of vinyl groups per molecule. For example, 2.02 g of a hydrogen-terminated siloxane having a molecular weight of about 1818 and 75 g of a vinyl-terminated siloxane having a molecular weight of 67,500 were mixed with 425 g of octamethylcyclotetrasiloxane. The mixture was stirred as described above and 10 ppm of platinum catalyst was added. The mixture was heated to 80 ° C. for 5 hours. The product was cooled and isolated. Viscosity 2
It was 88.5 centistokes at 5 ° C. The results demonstrate that siloxane polymers made with low functionality components have a low degree of cross-linking and therefore are less efficient at adjusting the viscosity of volatile siloxanes.

Elastomer Solids Content The percent solid elastomer in the product was determined by placing a weighed sample in a 150 ° C. oven for 45 minutes and observing the weight loss. Viscosity The viscosity of the elastomer / volatile siloxane solution after processing under flow induced shear and elongation was measured 24 hours after placing the processed sample in a Brookfield RVT viscometer with a 4 RPM TC spindle. did.

Cosmetic Evaluation Elastomer / volatile siloxane samples were evaluated for the presence of "gel spheres" by applying a small amount of the sample to the skin and spreading until the solvent spread and evaporated. During this process, the presence of undesirable silicone globules in poorly processed materials was observed.

Particle size analysis was carried out using a Malvern Mastersizer ™ with a 300 mm lens. The measured particle size varies with different types of devices used for measuring the particle size. It is believed that the particle size can be determined unconditionally, but in practice it depends on the machine used to measure the particle size. Therefore, the particle sizes described herein are based on the Malvern Mastersizer.
If other practitioners use other machines, they must be referenced or calibrated to the grain size determined by the Malvern Mastersizer. The desired material (10 g), typically swollen 90-95% cyclic siloxane with 5-10% elastomer, was dissolved in a 50/50 mixture (40 g) of isopropanol (IPA) and decamethylcyclopentasiloxane (D5). This solution was then added to approximately 500 g of 50/50 IPA / D5 previously placed in the Malvern Mastersizer reservoir. The resulting solution was circulated in the instrument for 5 minutes, and the measurement was performed three times in duplicate. Measurement limit with Malvern Mastersizer is 1 to 6 with 300mm lens
Range of 00 microns. A 45 mm lens was also used to look for smaller particles, but no significant number was found. Particles larger than 600 microns that could give rise to gel spheres were not visible with this method.

In earlier experiments, the particles prepared according to the invention did not swell well in thin materials such as 5% elastomer content and 95% cyclic siloxane. However, when the elastomer is further diluted to less than about 3% elastomer content, the particles swell completely. Thus, although the particle size measured in this experiment is for fully diluted particles, the actual volume used in most applications will be smaller depending on the amount of solvent available. For a given particle composition, it is possible to measure how much additional solvent can be absorbed, so that knowing the size of the sufficiently diluted particles, it is possible to calculate the particle size back at any concentration.
It is also within the scope of the present invention to prepare relatively small particles at a relatively high elastomer concentration and then swell it with an additional solvent to a large particle size.

Example 4 Preparation of Elastomer Sample An elastomer sample was prepared by mixing and mixing low molecular weight volatile siloxane, vinyl siloxane and silyl hydride. Subsequently, a platinum catalyst was added and the elastomer was cured by slowly heating to 80 ° C. This operation was performed with agitation to promote the resulting elastomer to be broken into pieces to be compatible with the subsequent processing steps.

For example, a typical example is [(HMe ₂ SiO) ₂ SiO] ₄ 7.28 with a hydride content of 0.92%.
g, 1500 g of vinyl-terminated polysiloxane having a vinyl content of 0.089% and decamethylcyclopentasiloxane 4
500 g was placed in a 10 liter Drais mixer and mixed at 20 ° C. Next, a platinum catalyst was added, and the temperature was slowly raised to 80 ° C., and the temperature was kept for 2 hours. The product was then removed from the Draise mixer and used in the following examples.

Example 5 Dilution The 25% elastomer / volatile siloxane prepared above was further diluted with the same or a different low molecular weight siloxane before subjecting it to high flow induced shear and elongation. Generally, the 25% elastomer / volatile siloxane was diluted to a solid elastomer content of about 5-7% to facilitate processing and add additional stress to the crosslinked polysiloxane particles.

In a typical example, 450 g of 25% elastomer / volatile siloxane was added to 1550 g of decamethylcyclopentasiloxane and swollen before processing.
After processing, the solution was checked for solid elastomer content by the above method and found to be 5.62%. Example 6 Sonorator Processing Material The above diluted solution of elastomer / volatile siloxane was pumped into the sonolator unit such that the orifice was maintained at a constant pressure. The size of the orifice was changed in several experiments. The throughput was then measured to determine the flow rate. The processing was performed by batch-wise passage or recirculation to the supply chamber. In the latter case, the number of passes was determined from the processing amount and the processing time. Samples were taken directly at the desired time intervals from the end of the sample loop.

Gaullen Homogenizer The Gaulen homogenizer was operated on the diluted sample in the same manner as the sonolator, with respect to feed, batch pass and passage over time. Pressure measurements were taken from the pressure measured in the feed chamber adjusted by the pressure setting on the orifice spin.

Microfluidizer The microfluidizer was generally supplied with material that had been pre-diluted and reduced in particle size from well over 1 mm to an average of about 1000 microns in a rotor / stator mixer. Next, the material was fed to the microfluidizer by batchwise passage. The microfluidizer was operated using two chambers. In all cases, the first was the H30Z chamber and the second was the J30
It was either a Y chamber or a smaller J20Y chamber.

Pressure Related Experiment A) The 25% elastomer / volatile siloxane product prepared above was diluted with pentamethylcyclopentasiloxane to a solid elastomer content of about 5.5%. This material was circulated through the sonolator at 300 psi and sampled as follows. Number of passes 11.25 33.75 56 112 Viscosity 23150 23450 22450 20100 Cosmetic Gel sphere Gel sphere Gel sphere Gel sphere In this experiment, at low pressure, the material was broken down into sufficiently small particles even with a very large number of cycles. This indicates that a high-viscosity material that meets beauty standards was not formed.

B) Similarly, 25% elastomer / volatile siloxane was diluted to 5.62% with decamethylcyclopentasiloxane. This material is
Processed at 000 psi and sampled as follows. Number of passages 18 30 Viscosity 40000 33000 Beauty Slight gel sphere No gel sphere Particle size Center and volume area% of peak 23.5 μm 0.50% 2.54% 36.5 8.04 19.23 53.0 24.23 31 .93 65.1 46.30 71.7 66.52 C) The 25% elastomer / volatile siloxane prepared as above was converted to 5.5 with decamethylcyclopentasiloxane.
%. This material is 4500ps with a sonolator
The sample was processed at i and sampled as follows.

No. of passes 3 4 Viscosity Beauty No gel sphere No gel sphere Particle size Center and volume% of peak 13.4 μm 0.08% 0.28% 23.3 3.70 9.11 36.2 9.37 9. 14 52.0 12.46 18.31 71.5 74.40 75.0 63.16 Examples 6, A, B and C process crosslinked polysiloxanes with increased flow induced shear and elongation due to increased pressure. It shows that a much faster and more economical way of processing (reaching acceptable cosmetic standards with a low number of passes) is provided. At the same time, the viscosity of the product is dramatically higher in high flow induced shear and elongation samples, notable in that less cross-linked polysiloxane is required in formulations where high viscosity cream maintenance is important. Is an advantage. From the contrast of the particle sizes of B and C in Example 6, the material produced in three passes at high flow induced shear and elongation shows low flow induced shear
It can be seen that the particle size distribution is wider (more for both large and small particles) than the equivalent sample produced by elongation. The result is
High flow induced shear and elongation samples have the advantage of having both high viscosity due to large particle size and smooth feel when applied to the skin due to small particle size.

Example 7 A) A 25% elastomer / volatile siloxane sample prepared as described above was diluted to 5% with an 85/15 blend of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. The material was processed at 4000 psi with the Gaulin homogenizer described above and sampled as follows.

Number of passages 11 45 Viscosity 2640 20300 Cosmetic Gel sphere A few gel spheres Particle size Center and volume% of peak 23.3 4.32 36.2 11.88 54.3 28.56 88.3 55.23 B) A 25% elastomer / volatile siloxane sample prepared as described above was diluted to 5% with an 85/15 blend of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. The material was processed at 7000 psi with the Gaulin homogenizer described above and sampled as follows.

Number of passes 5 Viscosity 78100 Beauty No gel sphere Particle size Peak center and volume% 23.3 5.73 36.2 7.48 52.0 20.26 88.4 66.52 For A and B of Example 7 The contrast shows that as the flow-induced shear and elongation increase with increasing pressure, the number of passes required to produce an acceptable product without gel spheres is significantly reduced. In addition, high flow induced shear and elongation results in high viscosity. The particle size after 5 passes with high flow induced shear and elongation is wider than the particle size after 45 passes with low flow induced shear and elongation. This result is advantageous in that it provides high viscosity with large particles and excellent feel and flow properties with small particle size.

Example 8 A) A 25% elastomer / volatile siloxane sample prepared as described above was diluted to 5% with an 85/15 blend of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. The material was processed in a microfluidizer at 6000 psi and sampled as follows.

Number of Passes 1 Viscosity <10000 Beauty Gel Sphere B) A 25% elastomer / volatile siloxane sample prepared as described above was diluted to 5% with an 85/15 blend of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. . The material was processed in a microfluidizer at 18000 psi and sampled as follows.

Number of passes 1 Viscosity> 60000 Beauty No gel spheres C) Dilute the 25% elastomer / volatile siloxane sample prepared as above to 5% with an 85/15 blend of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane did. The material was processed at 16000 psi in a microfluidizer using a large J30Y chamber and sampled as follows.

Number of passes 1 Viscosity 84400 Beauty No gel sphere Particle size Peak center and volume% 24.3 1.49 36.1 3.91 51.3 6.98 71.2 34.58 117.7 53.03 Examples 8, A, B and C, when the pressure in the microfluidizer is increased to increase the flow induced shear and elongation, the product is efficiently processed into a material that meets the cosmetic criteria with the desired high viscosity. Which indicates that. High flow induced shear and elongation also results in a broad particle size distribution.

Orifice Size Related Experimental Example 9 A) A 25% elastomer / volatile siloxane sample prepared as described above was diluted to 5% with an 85/15 blend of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. The material was processed at 16000 psi with a microfluidizer using a small J20Y chamber and sampled as follows.

Number of passes 1 Viscosity 172750 Beauty No gel sphere Particle size Peak center and volume% 23.5 0.12 35.8 0.62 51.9 2.83 72.7 5.10 132.7 91.33 Examples From comparison between Example 9 and Example 8C, it can be seen that reducing the orifice size while maintaining the pressure narrows the width of the particle size distribution.

Example 10 A) A 25% elastomer / volatile siloxane prepared as described above is 5.5 with decamethylcyclopentasiloxane.
%. The material was processed at 4500 psi with a 0.0021 orifice sonolator and sampled as follows.

Number of passes 1 Viscosity NA Cosmetic Gel sphere Particle size Peak center and volume% 23.4 0.69 35.8 2.16 56.7 15.72 111.5 81.43 B) 25 prepared as described above % Elastomer / volatile siloxane with decamethylcyclopentasiloxane 5.5
%. The material was processed at 4500 psi in a sonolator with orifice size 0.0008 and sampled as follows.

Number of passes 1 Viscosity NA Cosmetic Gel sphere Particle size Center and% by volume of peak 23.4 0.39 35.8 1.63 60.7 22.21 111.5 75.77 Example 11 A) Manufacture as above 5.5% of the 25% elastomer / volatile siloxane thus obtained with decamethylcyclopentasiloxane.
%. The material was processed at 4500 psi with a 0.0021 orifice sonolator and sampled as follows.

Number of passes 2 Particle size Peak center and volume% 23.5 1.32 36.4 4.35 51.8 7.90 71.5 20.06 118.9 66.36 B) Produced as described above. 5.5% of 25% elastomer / volatile siloxane with decamethylcyclopentasiloxane
%. The material was processed at 4500 psi in a sonolator with orifice size 0.0008 and sampled as follows.

Number of passes 2 Particle size Peak center and volume% 23.4 1.39 36.4 4.62 52.0 7.84 71.4 21.09 120.0 65.05 A and B of Example 10 This demonstrates that the width of the particle size distribution has been widened with a wide orifice size. In these examples, the crosslinked elastomer was not subjected to enough shear to reach the desired cosmetic standard without gel spheres and was passed several more times. After several more passes in Examples 8A and B, the particle size distribution at each orifice size was similar as a result of randomizing the position of the particles as they passed through the orifice. In general, the effect of orifice size on particle size distribution is less pronounced in a sonolator than in a microfluidizer, reflecting the shorter orifice path length. Due to the short path length of the sonolator, large flow-induced shear and particle elongation occur as the material is compressed before entering the orifice. This is the same for any orifice size, so that there is little change with the orifice size.

Viscosity-Related Experimental Example 12 A 25% elastomer / volatile siloxane prepared as described above was diluted to 5.5% with decamethylcyclopentasiloxane. 10% by weight of polydimethylsiloxane having a viscosity of 350 cps was added thereto and mixed. It has been observed that the polydimethylsiloxane oil does not completely penetrate the crosslinked polysiloxane elastomer, but rather coats its surface causing a dramatic decrease in viscosity. This decrease in viscosity was observed throughout all processing steps.

The above material was processed at 1000 psi with a sonolator having an orifice size of 0.0008 and sampled as follows. Number of passages 11 22 34 45 56 Viscosity 400 400 400 400 400 400 Beauty Gel sphere Gel sphere No gel sphere Particle size Center and volume% of peak Number of passages 11 22 34 45 56 12.8 00 00 0 23 0.05 0.05 0.18 0.40 0.33 0.22 36 0.58 1.83 3.52 4.03 4.50 56 22.79 18.11 10.03 7.27 64 14.58 75 85.60 88.01 90 77.98 99 75.20 140 84.79 Comparing Example 12 and Example 6B, performed at the same pressure, shows that viscosity is of critical importance in producing a particle size range.
For example, if the viscosity is reduced to about 400 ctks, the particle size will remain too large with further cycles and small particles will form only very slowly. At low viscosities, the flow induced shear and elongation to break up the particles is low.

Particle Size Distribution Characteristics Experiment In producing the material of the present invention by the method of the present invention, the three particle size ranges required for the composition of the present invention are determined according to the number of passages at a predetermined pressure. The materials can be produced in such proportions that the proportions are different and give a subjective difference in feel.

[0088]

[Table 9]

Materials having a large average particle size of 100 to 600 microns have a dense consistency similar to commercial gelatin foods. When applied to the skin, the material is difficult to apply to the skin, sticks rather than spreads on the skin, does not easily hydrate the skin, and does not form a thin film.

[0090]

[Table 10]

Materials having a medium average particle size in the range of 50 to 150 microns have a smooth, creamy pudding-like consistency. When applied to the skin, the material exhibits some resistance when applied to the skin, creating a cushion or sponge-like feel and providing a subjective sense of well-being.

[0092]

[Table 11]

Materials having a small average particle size have a thin fluid-like consistency. When applied to the skin, the material spreads readily on the skin with little or no resistance and produces an initially heavy or tacky feel. But,
Once applied to the skin, this substance gives the skin a smooth, silky feel. In addition, 3 of the composition of the present invention
All three examples have a particular granularity characteristic of the present invention.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Donald Scott Johnson United States of America, New York, Scotia, St. Stephen's Lane West, No. 91 (72) Inventor John Alfred Kilgoe United States of America, Cliffton Park, New York, Royal Oak Drive, No. 18 (72) Inventor Richard Dee Wang, United States, New York, Lexford, River Crest Drive, No. 14

Claims (2)

[Claims] 1. a) subjecting a dispersion of an elastomer having an initial average particle size and particle size distribution in a solvent to a pressure, b) subjecting the dispersion to a pressure drop through an orifice so that the dispersion has an orifice C) repeating steps a) and b), whereby the particle size distribution is adjusted so that the particle size distribution is in the range of from about 21 to about 26 microns. E) including a maximum in the range of about 33 to about 38 microns, and f) including a maximum in the range of about 50 to about 60 microns. 2. A) A dispersion in which an elastomer having an initial average particle size and a particle size distribution is dispersed in a solvent is subjected to a pressure drop using an orifice, whereby the dispersion passes through the orifice and the initial average of the dispersion is obtained. B) repeating step a), thereby adjusting the particle size distribution so that the particle size distribution is c) maximal in the range of about 21 to about 26 microns; d) in the range of about 33 to about 38 microns. Maximizing, and e) making the maxima in the range of about 50 to about 60 microns.